A student measured the diameter of a small  steel ball using a screw gauge of least count $0.001\, cm.$ The main scale reading is $5\, mm$ and zero of circular scale division coincides with $25$ divisions above the reference level. If screw gauge has a zero error of $-0.004 \,cm,$ the correct diameter of the ball is

Diagrams show readings of a screw gauge. figure $(i)$ shows the zero error reading when the screw gauge is closed, figure $(ii)$ the reading when the screw gauge is being used to measure the diameter of a ball-bearing. What is the diameter of the ball-bearing in $mm$? There are $50$ divisions on circular scale

In a screw gauge, there are $100$ divisions on the circular scale and the main scale moves by $0.5\,mm$ on a complete rotation of the circular scale. The zero of circular scale lies $6$ divisions below the line of graduation when two studs are brought in contact with each other. When a wire is placed between the studs, $4$ linear scale divisions are clearly visible while $46^{\text {th }}$ division the circular scale coincide with the reference line. The diameter of the wire is $...........\times 10^{-2}\,mm$

In a vernier callipers, each $cm$ on the main scale is divided into $20$ equal parts. If tenth vernier scale division coincides with nineth main scale division. Then the value of vernier constant will be $\dots \; \times 10^{-2} \;mm$

A screw gauge of pitch $0.5\,mm$ is used to measure the diameter of uniform wire of length $6.8\,cm$, the main scale reading is $1.5\,mm$ and circular scale reading is $7$. The calculated curved surface area of wire to appropriate significant figures is $......cm^2$ . [Screw gauge has $50$ divisions on the circular scale]

Using screw gauge of pitch $0.1$ $cm$ and $50$ divisions on its circular scale, the thickness of an object is measured. It should correctly be recorded as